The verdict on Apple's new map app: Compared with Google Maps, it sucks

FORTUNE — “Here’s the thing,” Daring Fireball‘s John Gruber wrote in May when 9to5Mac first reported that Apple

was about to replace Google’s

iOS Map app with its own. “Apple’s homegrown mapping data has to be great. Mapping is an essential phone feature. It’s one of those handful of features that almost everyone with an iPhone uses, and often relies upon.”

The centrality of mapping (second only to e-mail) seems to have slipped Gruber’s mind when he wrote his glowing review of the iPhone 5 running iOS 6 — the first version of Apple’s smartphone platform to be issued with Apple’s map app, rather than Google’s, on the home screen.

Among the reviewers who do mention it, however, the verdict is pretty much unanimous: Compared with Google Maps, Apple’s map app sucks.

“At one point as I was driving south on San Francisco’s Embarcadero, it thought I was going north; at another point, it mistakenly thought I was on Fremont Street, a couple of blocks away. I encountered a similar issue walking in downtown San Francisco.”

The most biting comments come from Waze CEO Noam Bardin in an interview with Business Insider‘s Megan Rose Dickey.

Bardin, it must be said, has a pony in this race, since Apple partnered with both Waze and Tom Tom for turn-by-turn navigation data and seems to have relied more heavily on the latter. Still, you might expect Bardin to be rooting for his partner’s app. It certainly doesn’t sound that way:

“Apple went out and partnered with the weakest player,” he told Dickey. “They’re now coming out with the lowest, weakest data set and they’re competing against Google, which has the highest data set. What’s going to happen with the Apple maps, is that you’re literally not going to find things. When you do find them, they might be in the wrong place or position geographically. And if you do have it, the route to it may not be the optimal route.”

Google has said it is going to continue to make a native version of its map app for iOS 6 — albeit with ads and not pre-loaded on the home screen. It Apple approves the Google app, you should be able to download it — for free — from the App Store and, if you like, move it to the iPhone’s home screen. You won’t be able to get rid of the ads.